Medical research out of the University of British Columbia suggests the number of children taking medications known as atypical antipsychotics has increased tenfold over the past decade, CBC News has learned.

The drugs — a class of medicines used to treat psychosis and other mental and emotional conditions — can have potentially serious side-effects, and are linked to increases in stroke and sudden death in adults.

Health Canada has not approved atypical antipsychotics for children.

"None of the atypical antipsychotics approved in Canada [Risperidone, Quetiapine, Olanzapine, Clozapine, Paliperidone, Ziprasidone] are indicated for use in children," Philippe Laroche, a Health Canada spokesman, told CBC News in an email on Thursday.

Colin Dormuth is an epidemiologist who reviewed all prescriptions involving atypical antipsychotics and written for children in B.C. over the last decade.

He says he found a tenfold increase in prescriptions of atypical antipsychotics for children 14 and under. Also called neuroleptics or second-generation antipsychotics, they include risperidone (Risperdal), quetiapine (Seroquel) and olanzapine (Zyprexa).

Dormuth was surprised at the young age of some of the children on the powerful medications, he told CBC.

Prescribing anti-psychotics is not justified when there is not adequate safety information to prove children won't be harmed, said Dormuth, who works with UBC's Therapeutics Initiative, which carries out independent reviews of the effectiveness and safety of medicines.

"It's definitely weighted towards 11-, 12-, 13-, 14-year-olds, but we do see instances as young as one year of age," Dormuth said.

Serious behavioural problems

Janice Dyett's 12-year-old son takes Risperdal to control the aggressive outbursts that had him kicked out of several Windsor, Ont., schools.

"If he's able to maintain his day and get along better, it's definitely worth it," Dyett told CBC News.

Dr. Tamison Doey, a psychiatrist in Windsor, is studying the drugs' effect on children with serious behavioural problems.

"We've seen children, who were unable to attend a regular school or even live at home, be able to return home and go back to regular school. So, that's a tremendous benefit," Doey, chief of psychiatry at Hôtel-Dieu Grace Hospital, told CBC News.

"The most impressive thing is talking to the children themselves. They will tell me that their anger is out of control, that they hate living like that.

"They're quite happy to find that there's something that will help them be able to have better control over themselves," said Doey,

"Despite the fact we have a lot of clinical experience with them, we don't have as much good data as we would like to show exactly how safe they are and what doses we should use."

Side-effects possible, psychiatrist warns

Doey said patients and their parents are informed about possible side-effects of the drugs.

"We tell them that it's a possibility they could have some neurological side-effects. These are much more common in the older drugs and not in the newer drugs," she said.

One rare side-effect could be a "late-occurring development of shaking or muscular movements," Doey said.

According to a 2006 Health Canada report on mental illness, 15 per cent of Canadian children, or 1.2 million, are affected by mental illness.

The percentage of adolescents aged 15-24 who reported mental illness was 18 per cent, according to the report.

As well, 80 per cent of all psychiatric disorders emerge in adolescence, the report said, noting those disorders "are the single most common illness that onset in the adolescent age group."